Thousands evacuated as Philippines powerful Mayon Volcano threatens

Around 20,000 Filipinos were evacuated from the slopes of the Mayon Volcanoe on the Philippines' main island of Luzon Tuesday. The volcano, which has erupted and left fatalities in the past, is a reminder of dangers of living on the Pacific "ring of fire."

ByDan Murphy, Staff writerDecember 15, 2009

A view of the Mayon volcano is seen from Legazpi city, Philippines on Tuesday. On Tuesday the Philippines evacuated around 20,000 people from the slopes of Mt. Mayon, one of the country's deadliest volcanoes, as plumes of ash exploded skyward and lava oozed down its upper slopes.

On Tuesday The Philippines evacuated around 20,000 people from the slopes of Mt. Mayon, one of the country's deadliest volcanoes, as plumes of ash exploded skyward and lava oozed down its upper slopes.

Mayon is a stratovolcano, the cone-shaped variety that are both the most beautiful and often the most deadly. Mt. Fuji in Japan is a stratovolcano. So is Mt. Kilamanjaro in Tanzania, just over the Kenyan border.

More ominously so is Mt. Pinatubo, like Mayon on the Philippines main island of Luzon. In June 1991, Pinatubo erupted in fury, the second largest eruption recorded in the 20th century. Weeks of preparation had seen 60,000 people evacuated from the surrounding area before the eruption, but it still claimed about 800 lives, mostly due to houses collapsing under the weight of accumulated ash.

The Pinatubo eruption had more explosive force than the nuclear bombs the US dropped on Japan at the end of WWII. It pumped millions of tons of ash and sulfur dioxide into the atmosphere which, among other things, led to an average drop in global surface temperatures of about 1 degree F over the next year.

Similar preparations like those taken in advance of Pinatubo's eruption are being made in the event of an eruption by Mayon, including more evacuations if necessary and intense monitoring by volcanologists.

Such measures have yielded dividends across the world since the early 20th century, when little was understood about the timing of eruptions and notification systems in the most at risk places - the vast majority of them the volcanically formed islands of the Pacific like those that dominate The Philippines and Indonesia.

The 1886 eruption of Mt. Krakatoa, a tiny island between the Indonesian islands of Java and Sumatra, by contrast claimed at least 30,000 lives.

To be sure, Mt. Mayon has been recently deadly. Mudslides formed of the loose ash on its slopes killed about 1,000 people in 2006.

The eruptions in the Philippines and surrounding locations are dangerous, but they are also givers of life.

The lava flows creeping down the slopes and falls of ash so great they can bury whole towns. But, over the long term, that activity brings minerals to the surface that creates rich soils that allow for intensive cultivation.

That has led to millions living in the shadows of volcanoes, like the residents around Mayon, which lies about 14 kilometers (9 miles) north of Legazpi City, which in turn is home to 150,00 people. The Associated Press reported that over 50,000 people live within a five-mile radius of the volcano.

About three-quarters of the world's active volcanoes are part of the Pacific ring of fire, a horseshoe-shaped area of intense seismic and tectonic activity that runs from New Zealand in the southwest, up along the coast of the Asian mainland and down the west coast of North and South America as far as southern Chile.